Pawl mechanism for horizontal type lifting jacks



Dec. 13, 1966 R. K. ULM 3,290,953

PAWL MECHANISM FOR HORIZONTAL TYPE LIFTING JACKS Original Filed Deo. 26. 1961 2 Sheets-Sheet 1 LLEEE/l K. Ulm

ATTORNEY 5 R. K. ULM

Dec. 13, 1966 PAWL MECHANISM FOR HORIZONTAL TYPE LIFTING JACKS 2 Sheets-Sheet 2 Original Filed Dec. 26, 1961 INVENTOR RLLESE/ K. L//rn ATTORNEYS United States Patent 3,290,953 IAWL MECHANISM FOR HORIZONTAL TYPE LIFTING .IACKS Russell Keith Ulm, Butler, Ind., assigner to Universal Tool & Stamping Company, Inc., Butler, Ind., a corporation of Indiana Original application Dec. 26, 1961, Ser. No. 162,087, now Patent No. 3,173,660, dated Mar. 16, 1965. Divided and this application Dec. 3, 1964, Ser. No. 415,694

4 Claims. (Cl. 741-1415) This application is a division out of U.S. application Serial No. 162,087, led December 26, 1961, now U.S. Patent 3,173,660, dated March 16, 1965.

The primary object of the present invention is the provision of an improved pawl mechanism for horizontal type lifting jacks.

A further object of this invention is the provision of a ruggedly constructed pawl mechanism for lifting jacks having improved means so mounted with respect to a rack bar that it will slide therealong without lateral shifting; clearances being provided so that when it is used in a horizontal type jack structure the pawl mechanism will have just sufficient clearances in its rack bar to permit sliding action of the pawl construction without any unnecessary lateral and vertical shifting movements.

Other objects and advantages of this invention will be apparent during the course of the following detailed description.

In the accompanying drawings, forming a part of this specification, and wherein similar reference characters designate corresponding parts throughout the several views:

FIG. 1 is a perspective view of the improved jack slide carriage showing its associated parts and supporting means for a pawl mechanism.

FIG. 2 is a vertical cross sectional view taken through `the rear end of a horizontal type jack bar showing the associated features of the improved pawl mechanism.

FIG. 3 is a transverse cross sectional view of a horizontal type rack bar showing how the improved pawl mechanism is mounted with respect thereto looking rearwardly along the rack bar from the forward end of the pawl mechanism.

FIGS. 4 and 5 are transverse cross sectional views taken substantially on the respective lines 1*4 and 5--5 of FIG. 2.

In the drawings, wherein for the purpose of illustration, is shown a preferred embodiment of the invention, the letter A may generally designate a horizontal type jack structure more specifically detailed in U.S. Patent 3,173,660, dated March 16, 1965, of which the present application is a division.

The jack structure includes a rack bar B and a load lifting assemblage C of which the pawl mechanism D is a part.

The rack bar B preferably is a one-piece construction which is formed of rolled steel and shaped to provide a wide horizontal bottom wall 21 having upstanding vertical side walls 22 and 23; said side walls at the upper ends thereof being provided with inturned horizontal flanges 24 lying in the same plane and dening a trackway 24a along which the improved pawl mechanism D is adapted to slide. The rack bar in cross section may be said to have a polygonal or rather rectangular shape. It will be noted that the trackway 24a comprises facing channels. The bottom wall 21 centrally is provided with a longitudinal series of teeth 30.

The rack bar B at its rear end is provided with a base plate 41 which consists of a bottom wall 50 riveted or bolted at 51 to the rack bar bottom wall 21. An end wall 52 is vertically positioned and connected to the bottom wall 50 to close the channel or trackway 24a of the rack bar B. It is over llanged at 53 upon the rack bar, as shown in FIG. 2.

The load lifting assemblage C is described in the application of which this is a division and includes, for the purposes of the present invention, a lifting beam 66.

The pawl mechanism D comprsies a slide carriage 67 including a casing or housing to which the jack load lifting beam 66 is connected by a detachable pin 88, as shown in FIG. 2.

The pawl mechanism D is intended to slide entirely within the trackway or passageway 24a of the rack bar B. No part of it protrudes either laterally or beneath the rack -bar to provide an obstruction to ground contact as the carriage moves along the bar B.

As before mentioned the pawl carriage preferably cornprises a casing or housing 90 which is shown in perspective in FIG. l and in various elevations and cross sectional views. It includes relatively spaced side walls 91 and 92 in parallelism, connected forwardly and rearwardly by bottom cross bars 93 and 94 respectively, best shown in cross section in FIG. 2. This provides a channel way. Midway of their heights the walls 91 and 92 are forwardly connected and braced by inturned shallow arm portions 95 which are spot welded at 96. Below these arm portions 95 the walls 91 and 92` are rearwardly extended and then laterally angled at at each side of the channel way in divergent relation; these portions 100 being adapted to ride in the side channels of the rack bar between the bottom wall 21 of the rack bar (laterally of the teeth 30) and the top iianges 24, as is shown in FIG. 3. Thus, the flanges 100 provide extensions which are slidable in the channels of the rack bar to prevent tilting of the pawl mechanism as the latter is moved along the rack bar. In lieu of these lateral slide flanges 100 anti-friction means may be substituted, such as is shown in U.S. Patent 3,180,619, dated April 27, 1965, for sliding along a rack bar, or rollers may be substituted. At the front end of the casing 90 rollers are provided at 104 on the outer ends of a pin 88, which roll along the trackway channels provided -at the sides of the rack bar between the wall 21 and the flanges 24, as can be noted from FIG. 4.

The carriage casing 90 supports a pawl mechanism, which is largely conventional. The same includes ya pawl actuating member which is socketed at 111 to receive a handle and pivoted on a detachable pin 113 mounted on the side walls of casing 90. Furthermore, the pawl mechanism includes a short pawl 112 pivoted on pin 113 mounted on the side walls of casing 90 and adapted to act upon the rack teeth of the rack bar B. A longer pawl 114 is pivoted on the actuating member 110 rearwardly and slightly upwardly of the pawl 112, upon a pin 115 carried by side walls 91 and 92 and likewise adapted to act on the rack teeth of the bar 20. A looped steel spring 116 is provided in the case 90 connected at one end at 117 with the free end of the longer pawl 114 and at its opposite end being connected at 118 to the free end of the shorter pawl 112. The function of this spring is to urge the free ends of the pawl into engagement with the rack teeth 30. A trip lever 120 is pivoted at 121 upon the case 90 having an inturned end 120a for engagement with the intermediate or bight portion of the spring 116. When in the position shown in FIG. 2 the spring induces a compressive force large enough to overc-ome both the tensile and compressive forces introduced into the spring by the alternate up and down movement of the longer pawl. When the trip lever 120 is lowered out of operation the up and down movement of the handle of the jack and the member 110 will result in the jack retracting along the horizontal rack bar. The shorter pawl 112 will engage the teeth 30 of the rack bar and the load will he transferred from the short pawl 112 to the long pawl 114. The jack lifting assemblage moves forwardly along the rack bar when the handle is moved downwardly and when the handle is rotated upwardly the longer pawl is pulled upwardly into the next tooth of the rack bar in accordance with well known operation of such pawl mechanism.

The case structure 90 does not carry any of the load except the reactionary force to push the beam 66 forward or let it come backward as the vehicle is raised or 1owered. All parts of the rack bar, base structure, leg, beam, carriage and pawl mechanism are constructed of durable rigid metal, such as steel.

It sh-ould be noted that the anti-friction rollers 1041i` a-nd the slide extensions 100 of the casing 90 are disposed within the side channels or trackways of the rack bar B with just sufficient clearance to permit them to move without any undue lateral or vertical movements.

Various changes in the size, shape and arrangement of parts may be made to the form of invention herein shown and described without departing from the spirit of the invention or scope of the claims.

I claim:

' 1. In a jack mechanism the combination of a jack slide casing comprising a pair of spaced side walls rigidly connected together, a jack actuating pawl mechanism operatively mounted between and upon said side walls, said side walls at an end of the casing being provided with lateral outwardly extending guides at the 'lower portions of said side walls, said side walls above said guide exten- `sions having inturned rigidly connected flanges bracing said side Walls in their relatively spaced positions.

2. A jack mechanism as described in claim 1 in which the side walls at the lower portions of the ends of said side walls opposite said extensions are provided with a shaft having a roller on each of the ends thereof at the outer side of each of said side walls.

3. In a jack mechanism the combination of a jack slide casing comprising a pair of spaced side walls rigidly connected together to dene a channei way, a jack actuated pawl mechanism operatively mounted upon said side walls and located in said channel way, said side walls at the terminal end of said channel way and at each side of the channel way being provided with outwardly extending guide anges, and extended guide means mounted upon said side walls at the opposite ends of said side walls and located at the outer sides of said side walls.

4. A jack mechanism as described in claim 3 in which the last mentioned guide means comprises a roller mounted at the outer side of each side Wall.

References Cited by the Examiner UNITED STATES PATENTS 2,630,297 3/1953 HunZ 74-577 FRED C. MATTERN, IR., Primary Examiner. 

1. IN A JACK MECHANISM THE COMBINATION OF A JACK SLIDE CASING COMPRISING A PAIR OF SPACED SIDE WALLS RIGIDLY CONNECTED TOGETHER, A JACK ACTUATING PAWL MECHANISM OPERATIVELY MOUNTED BETWEEN AND UPON SAID SIDE WALLS, SAID SIDE WALLS AT AN END OF THE CASING BEING PROVIDED WITH LATERAL OUTWARDLY EXTENDING GUIDES AT THE LOWER PORTIONS OF SAID SIDE WALLS, SAID SIDE WALLS ABOVE SAID GUIDE EXTENSIONS HAVING INTURNED RIGIDLY CONNECTED FLANGES BRACING SAID SIDE WALLS IN THEIR RELATIVELY POSITIONS. 